Does asyncio supports asynchronous I/O for file operations?
Most operating systems don't support asynchronous file operations.That's why asyncio doesn't support them either.
See the asyncio wiki for further explanation.
That depends on what library you use.
curio offers this functionality, see https://curio.readthedocs.io/en/latest/reference.html#module-curio.file
meanwhile, plain asyncio doesn't, although there are 3rd party libraries, e.g. https://github.com/Tinche/aiofiles (where synchronous file access isolated in threads)
Modern operating systems do provide asynchronous file primitives, but these are varied, thus each would need own implementation. Please compare:
- http://man7.org/linux/man-pages/man7/aio.7.html
- https://msdn.microsoft.com/en-us/library/windows/desktop/aa365683(v=vs.85).aspx
- https://developer.apple.com/library/content/documentation/FileManagement/Conceptual/FileSystemProgrammingGuide/TechniquesforReadingandWritingCustomFiles/TechniquesforReadingandWritingCustomFiles.html
I suspect someone will soon rip out underlying async io from node.js and make a decent Python library, or perhaps someone already has.
Specifically for Linux, there are low-level bindings in https://pypi.org/project/liburing/
For a solid overview of asynchronous IO APIs in Linux, circa 2020, see https://www.scylladb.com/2020/05/05/how-io_uring-and-ebpf-will-revolutionize-programming-in-linux/